Stimulation field modelling in an implantable stimulator device

Abstract

A field measurement algorithm and measuring circuitry in an implantable stimulator, and an field modelling algorithm operable in an external device, are used to determine an electric field in a patient's tissue. The field measuring algorithm provides at least one test current between two electrodes, and a plurality of voltage differentials are measured at different combinations of the electrodes. The voltage differential data is telemetered to the field modelling algorithm which determines directional resistance at different locations in the patient's tissue. The field modelling algorithm can then use a stimulation program selected for the patient and the determined directional resistances to determine voltages in the patient's tissue at various locations, which in turn can be used to model a more-accurate electric field in the tissue, and preferably to render an electric field image for display in a graphical user interface of the external device.

What is claimed is: 
     
       1. A method for communicating between an external device and a stimulator device having a plurality of electrode nodes, each electrode node configured to be coupled to one of a plurality of electrodes configured to contact a patient's tissue, the method comprising:
 receiving at a user interface of the external device a user input to cause the stimulator device to apply a plurality of test currents, wherein each test current is applied between different combinations of at least two of the electrode nodes; 
 determining a data set, wherein the data set comprises a plurality of measurements at different electrode nodes or at different combinations of the electrode nodes for each test current; 
 receiving information indicative of positions of the plurality of electrodes; 
 receiving potential stimulation parameters to be executed within the stimulator device; and 
 determining from the information, the data set, and the potential stimulation parameters a representation of an electric field in the patient's tissue. 
 
     
     
       2. The method of  claim 1 , wherein the information indicative of the positions of the plurality of electrodes and the potential stimulation parameters to be executed within the stimulator device are received at the external device. 
     
     
       3. The method of  claim 2 , further comprising receiving the data set at the external device from the stimulator device. 
     
     
       4. The method of  claim 3 , wherein the representation of the electric field in the patient's tissue is determined at the external device. 
     
     
       5. The method of  claim 1 , wherein the potential stimulation parameters comprise at least selected ones of the plurality of electrodes, and an amplitude of a current to be provided at each selected electrode. 
     
     
       6. The method of  claim 1 , wherein the user interface comprises at least one input to allow a user to enter the potential stimulation parameters. 
     
     
       7. The method of  claim 1 , further comprising rendering the representation of the electric field as an electric field image, and displaying in the user interface the electric field image superimposed on a lead image showing the plurality of electrodes. 
     
     
       8. The method of  claim 7 , further comprising receiving a tissue image, and displaying the tissue image on the user interface in relation to the electric field and lead images. 
     
     
       9. The method of  claim 8 , wherein the user interface comprises one or more inputs to allow a user to adjust a view of the displayed tissue image, electric field image, and lead image. 
     
     
       10. The method of  claim 1 , wherein the determined representation of the electric field is three-dimensional. 
     
     
       11. The method of  claim 1 , wherein determining the representation of the electric field comprises using the data set to determine a plurality of resistances between neighboring positions in three-dimensional space relative to the plurality of electrodes. 
     
     
       12. The method of  claim 11 , further comprising determining voltages at the positions in three-dimensional space in response to the potential stimulation parameters. 
     
     
       13. The method of  claim 1 , wherein the measurements comprise voltage measurements at the different electrode nodes or between the different combinations of the electrode nodes. 
     
     
       14. The method of  claim 13 , wherein the voltage measurements at the different electrode nodes or between the different combinations of the electrode nodes are measured during each of the test currents. 
     
     
       15. The method of  claim 13 , wherein the measurements comprise a plurality of single ended voltage measurements taken with respect to a reference potential at the different electrode nodes. 
     
     
       16. The method of  claim 13 , wherein the measurements comprise differential voltage measurements taken between the different combinations of the electrode nodes. 
     
     
       17. The method of  claim 1 , wherein the test currents comprise current pulses. 
     
     
       18. The method of  claim 17 , wherein the current pulses comprise biphasic current pulses. 
     
     
       19. An external device configured to communicate with a stimulator device having a plurality of electrode nodes, each electrode node configured to be coupled to one of a plurality of electrodes configured to contact a patient's tissue, the external device comprising:
 control circuitry configured to
 render a user interface, wherein the user interface is configured to receive a user input to cause the stimulator device to apply a plurality of test currents, wherein each test current is applied between different combinations of at least two of the electrode nodes, 
 determine a data set, wherein the data set comprises a plurality of measurements at different electrode nodes or at different combinations of the electrode nodes for each test current, 
 receive information indicative of positions of the plurality of electrodes, 
 receive potential stimulation parameters to be executed within the stimulator device, and 
 determine from the information, the data set, and the potential stimulation parameters a representation of an electric field in the patient's tissue. 
 
 
     
     
       20. A non-transitory computer readable media including instruction executable on an external device, wherein the external device is configured to communicate with a stimulator device having a plurality of electrode nodes, each electrode node configured to be coupled to one of a plurality of electrodes configured to contact a patient's tissue, wherein the instructions when executed are configured to:
 render a user interface, wherein the user interface is configured to receive a user input to cause the stimulator device to apply a plurality of test currents, wherein each test current is applied between different combinations of at least two of the electrode nodes; 
 receive a data set, wherein the data set comprises a plurality of measurements at different electrode nodes or at different combinations of the electrode nodes for each test current; 
 receive information indicative of positions of the plurality of electrodes; 
 receive potential stimulation parameters to be executed within the stimulator device; and 
 determine from the information, the data set, and the potential stimulation parameters a representation of an electric field in the patient's tissue.